I have an LG-E405 phone running Android 2.3.6.
I connected my phone with a USB cable and selected the mode as Charge Only.
Charge Only
Now when I try to tur
Finally figured out the solution to the problem, with the help of this post.
When you connect your phone to your PC, using the USB cable, select the mode as PC Software.
PC Software
Now you should be able to enable USB Debugging.